Appraisal of cytotoxicity and acrylamide mitigation potential of L-asparaginase SlpA from fish gut microbiome.

L-asparaginase catalyzes the hydrolysis of L-asparagine to L-aspartic acid and ammonia. It has application in the treatment of acute lymphoblastic leukemia in children, as well as in other malignancies, in addition to its role as a food processing aid for the mitigation of acrylamide formation in the baking industry. Its use in cancer chemotherapy is limited due to problems such as its intrinsic glutaminase activity and associated side effects, leading to an increased interest in the search for novel L-asparaginases without L-glutaminase activity. This study reports the cloning and expression of an L-asparaginase contig obtained from whole metagenome shotgun sequencing of Sardinella longiceps gut microbiota. Purified recombinant glutaminase-free L-asparaginase SlpA was a 74 kDa homodimer, with maximal activity at pH 8 and 30 °C. Km and Vmax of SlpA were determined to be 3.008 mM and 0.014 mM/min, respectively. SlpA displayed cytotoxic activity against K-562 (chronic myeloid leukemia) and MCF-7 (breast cancer) cell lines with IC50 values of 0.3443 and 2.692 U/mL, respectively. SlpA did not show any cytotoxic activity against normal lymphocytes and was proved to be hemocompatible. Pre-treatment of biscuit and bread dough with different concentrations of SlpA resulted in a clear, dose-dependent reduction of acrylamide formation during baking. KEY POINTS: • Cloned and expressed L-asparaginase (SlpA) from fish gut microbiota • Purified SlpA displayed good cytotoxicity against K-562 and MCF-7 cell lines • SlpA addition caused a significant reduction of acrylamide formation during baking.

BaCf3: highly thermostable bacteriocin from Bacillus amyloliquefaciens BTSS3 antagonistic on food-borne pathogens.

In the present study, we characterized bacteriocin BaCf3, isolated and purified from Bacillus amyloliquefaciens BTSS3, and demonstrated its inhibitory potential on growth and biofilm formation of certain food spoilage bacteria and pathogens. Purification was by gel filtration chromatography and its molecular weight was 3028.422 Da after MALDI-TOF MS. The bacteriocin was highly thermostable withstanding even autoclaving conditions and pH tolerant (2.0-13.0). The bacteriocin was sensitive to oxidizing agent (DMSO) and reducing agent (DTT). The de novo sequence of the bacteriocin BaCf3 was identified and was found to be novel. The sequence analysis shows the presence of a disulphide linkage between C6 and C13. The microtitre plate assay proved that BaCf3 could reduce up to 80% biofilm produced by strong biofilm producers from food samples. In addition, BaCf3 did not show cytotoxicity on 3-TL3 cell line.

Metabarcoding data of bacterial diversity of the deep sea shark, Centroscyllium fabricii.

This data article describes the bacterial diversity of the deep sea shark, Centroscyllium fabricii. The data was acquired by metabarcoding using 16S rDNA. Centroscyllium fabricii, a deep sea shark found at depths below 275 m was sampled during Sagar Sampada cruise no 305 in the Indian Ocean and metagenomic DNA was isolated from the gut contents using QIAamp DNA stool minikit. V3 region of 16S rDNA region was amplified and the amplicons were sequenced on Illumina MiSeq system using 151 bp × 2 paired end reads. The data of this metagenome is available in the BioSample Submission Portal as Bio-Project PRJNA431407and Sequence Read Archive (SRA) accession number SRR6507004.